This invention relates to an improvement in a seed drill of the type disclosed in my U.S. Pat. No. 3,177,830, which was issued on Apr. 13, 1965. Modifications of this type of seed drill are disclosed in my U.S. Pat. Nos. 3,319,590, issued May 16, 1967 and 3,385,243, issued May 28, 1968. The disclosures of my three prior patents are hereby incorporated within this disclosure by reference.
The seed drills disclosed in my referenced U.S. patents are designed for deep furrow seeding of crops. Seed is planted at the bottom of a furrow having packed sloped sides. This is accomplished by placing the seeds into soil behind a narrow shovel overlapped closely by single or paired press wheels. Each press wheel is mounted alongside the path of a shovel to pack the sloping sides of a deep furrow and assure accurate control of both planting depth and proper soil coverage over the seeds.
One problem encountered in fields where the sides of the furrows have been packed by the seed drill configurations shown in these prior patents is the tendency of the relatively deep, open furrows to concentrate snow and rain runoff, leading to soil erosion. Such erosion can wash out the planted crop within the furrows and aggravate adjacent environmental conditions, such as drainage into nearby streams or lakes. The tendency of water to flow along the packed furrow walls can also result in loss of critical moisture required for continuing nourishment and growth of the planted crop. The present invention incorporates a modification of the press wheel which leads to formation of transverse soil dams at longitudinally spaced positions across each packed furrow. These small dams impede or interrupt passage of water along the furrow length.
Various devices have been proposed in the past for intermittently damming agricultural furrows, both during field cultivation and during planting. One example of a dammer attachment for a furrow seeder is shown in U.S. Pat. No. 2,193,275, issued Mar. 12, 1940. The disclosed device comprises a transverse blade that intermittently scoops soil behind the furrow former as the blade is raised or lowered in the furrow.
A rotating attachment for forming dams in furrows behind a planter is shown in U.S. Pat. No. 2,098,738. The device utilizes radial scraper blades that project to the sides of arcuate wheel sections which press along the center of the seeded furrow.
Neither of the above devices has the capability of forming a furrow with tightly packed side walls. Both are concerned with forming transverse soil dams intermittently across loosely packed furrows. Scooping the soil within a furrow by use of a transverse blade that extends across the planted seeds risks the potential disturbance of the seeds unless depth control for the blade can be very accurately maintained, a condition almost impossible to guarantee, particularly when the soil surface is not perfectly level. Furthermore, the rolling engagement of the dammer shown in U.S. Pat. No. 2,098,738 would pack soil over the planted seeds, which can be detrimental to initial seed emergence. The present invention intermittently forms dams across packed sides of a furrow without subjecting the soil located vertically over the planted seeds to any vertical packing pressure.
Other devices for intermittently damming furrows are shown in U.S. Pat. Nos. 2,196,038, issued Apr. 2, 1940, 2,236,832, issued Apr. 1, 1941 and 2,780,975, issued Feb. 12, 1957. Operation of the devices shown in these patents appears to result in substantial soil disturbance within the furrow. They do not appear to be readily adaptable to usage within a furrow containing planted seeds.
U.S. Pat. No. 4,508,177, issued Apr. 2, 1985, shows a device for forming dams intermittently between the rows of a crop by use of a freely rotating spider mounted behind field cultivation shanks. It is designed for intermittently damming a field surface between the planted rows or furrows, rather than along such furrows. The unacceptable seed disturbance that would result were such a spider used along a planted furrow is believed to be obvious.
The known earlier equipment for producing intermittent dams in planted field areas or furrows are not applicable to the critical planting techniques used in dry land farming where grain seeds are accurately spaced along deep furrows having dry soil sides. Any damming accessory that disturbs th sides of a deep furrow without careful control risks collapse of the furrow walls and reduction in seed germination rates. Such damming methods can be used in irrigated farming, where seed is broadcast at relatively high seeding rates and loss of germination is of minor consequence. However, the deep furrows leading to a single row of carefully placed seed in moist soil cannot be disrupted, once they are formed, without serious crop loss. The present improvement forms carefully controlled dams simultaneously with packing of the furrow sides. This assures that the furrow will be intact and that no seed will be covered with soil at a level that will affect germination.
The present invention utilizes a recess that interrupts the continuity of a press wheel rim. As the press wheel rotates in engagement with the sides of a furrow, the recess leaves intermittent piles of soil across the furrow. The rear wall of the recess preferably includes a transverse tab projecting outwardly at the rim of the press wheel. The provision of such a tab, with or without an adjacent recess, assists the press wheel in clearing adjacent trash encountered by it in a field, particularly under no-till or minimum till seeding conditions. By angularly locating the tab adjacent to the termination of a straw walker typically mounted alongside the press wheel, one can eliminate the tendency of rocks to wedge between the press wheel and straw walker. The recess formed in the press wheel can be selectively closed by mounting a complementary insert to it. The insert will maintain the tab configuration on the press wheel to assure trash clearance and obstruction of rocks even when intermittent damming across the furrow is not desired.